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AES E-Library

Analytical and Perceptual Evaluation of Nonlinear Devices for Virtual Bass System

Nonlinear devices (NLDs) are generally used in virtual bass system (VBS). The prime objective is to extend the low frequency bandwidth psychoacoustically by generating a series of harmonics in the upper-bass and/or mid-frequency range where loudspeakers can reproduce well. However, these artificially added harmonics introduce intermodulation distortion and may change the timbre of the sound tracks. In this study, nine memoryless NLDs are studied based on objective analysis and subjective listening tests. The objectives of this work are (1) to quantify the spectral contents of NLDs when fed by single-tone; (2) to find out which type of NLDs is best for psychoacoustic bass enhancement through subjective listening tests and objective GedLee nonlinear distortion metric; and (3) to investigate whether there is any correlation between subjective listening tests’ results and objective performance scores.